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+//===- LiveInterval.cpp - Live Interval Representation --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the LiveRange and LiveInterval classes. Given some
+// numbering of each the machine instructions an interval [i, j) is said to be a
+// live range for register v if there is no instruction with number j' >= j
+// such that v is live at j' and there is no instruction with number i' < i such
+// that v is live at i'. In this implementation ranges can have holes,
+// i.e. a range might look like [1,20), [50,65), [1000,1001). Each
+// individual segment is represented as an instance of LiveRange::Segment,
+// and the whole range is represented as an instance of LiveRange.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/LiveInterval.h"
+#include "LiveRangeUtils.h"
+#include "RegisterCoalescer.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/CodeGen/LiveIntervals.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/MC/LaneBitmask.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <iterator>
+#include <utility>
+
+using namespace llvm;
+
+namespace {
+
+//===----------------------------------------------------------------------===//
+// Implementation of various methods necessary for calculation of live ranges.
+// The implementation of the methods abstracts from the concrete type of the
+// segment collection.
+//
+// Implementation of the class follows the Template design pattern. The base
+// class contains generic algorithms that call collection-specific methods,
+// which are provided in concrete subclasses. In order to avoid virtual calls
+// these methods are provided by means of C++ template instantiation.
+// The base class calls the methods of the subclass through method impl(),
+// which casts 'this' pointer to the type of the subclass.
+//
+//===----------------------------------------------------------------------===//
+
+template <typename ImplT, typename IteratorT, typename CollectionT>
+class CalcLiveRangeUtilBase {
+protected:
+ LiveRange *LR;
+
+protected:
+ CalcLiveRangeUtilBase(LiveRange *LR) : LR(LR) {}
+
+public:
+ using Segment = LiveRange::Segment;
+ using iterator = IteratorT;
+
+ /// A counterpart of LiveRange::createDeadDef: Make sure the range has a
+ /// value defined at @p Def.
+ /// If @p ForVNI is null, and there is no value defined at @p Def, a new
+ /// value will be allocated using @p VNInfoAllocator.
+ /// If @p ForVNI is null, the return value is the value defined at @p Def,
+ /// either a pre-existing one, or the one newly created.
+ /// If @p ForVNI is not null, then @p Def should be the location where
+ /// @p ForVNI is defined. If the range does not have a value defined at
+ /// @p Def, the value @p ForVNI will be used instead of allocating a new
+ /// one. If the range already has a value defined at @p Def, it must be
+ /// same as @p ForVNI. In either case, @p ForVNI will be the return value.
+ VNInfo *createDeadDef(SlotIndex Def, VNInfo::Allocator *VNInfoAllocator,
+ VNInfo *ForVNI) {
+ assert(!Def.isDead() && "Cannot define a value at the dead slot");
+ assert((!ForVNI || ForVNI->def == Def) &&
+ "If ForVNI is specified, it must match Def");
+ iterator I = impl().find(Def);
+ if (I == segments().end()) {
+ VNInfo *VNI = ForVNI ? ForVNI : LR->getNextValue(Def, *VNInfoAllocator);
+ impl().insertAtEnd(Segment(Def, Def.getDeadSlot(), VNI));
+ return VNI;
+ }
+
+ Segment *S = segmentAt(I);
+ if (SlotIndex::isSameInstr(Def, S->start)) {
+ assert((!ForVNI || ForVNI == S->valno) && "Value number mismatch");
+ assert(S->valno->def == S->start && "Inconsistent existing value def");
+
+ // It is possible to have both normal and early-clobber defs of the same
+ // register on an instruction. It doesn't make a lot of sense, but it is
+ // possible to specify in inline assembly.
+ //
+ // Just convert everything to early-clobber.
+ Def = std::min(Def, S->start);
+ if (Def != S->start)
+ S->start = S->valno->def = Def;
+ return S->valno;
+ }
+ assert(SlotIndex::isEarlierInstr(Def, S->start) && "Already live at def");
+ VNInfo *VNI = ForVNI ? ForVNI : LR->getNextValue(Def, *VNInfoAllocator);
+ segments().insert(I, Segment(Def, Def.getDeadSlot(), VNI));
+ return VNI;
+ }
+
+ VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Use) {
+ if (segments().empty())
+ return nullptr;
+ iterator I =
+ impl().findInsertPos(Segment(Use.getPrevSlot(), Use, nullptr));
+ if (I == segments().begin())
+ return nullptr;
+ --I;
+ if (I->end <= StartIdx)
+ return nullptr;
+ if (I->end < Use)
+ extendSegmentEndTo(I, Use);
+ return I->valno;
+ }
+
+ std::pair<VNInfo*,bool> extendInBlock(ArrayRef<SlotIndex> Undefs,
+ SlotIndex StartIdx, SlotIndex Use) {
+ if (segments().empty())
+ return std::make_pair(nullptr, false);
+ SlotIndex BeforeUse = Use.getPrevSlot();
+ iterator I = impl().findInsertPos(Segment(BeforeUse, Use, nullptr));
+ if (I == segments().begin())
+ return std::make_pair(nullptr, LR->isUndefIn(Undefs, StartIdx, BeforeUse));
+ --I;
+ if (I->end <= StartIdx)
+ return std::make_pair(nullptr, LR->isUndefIn(Undefs, StartIdx, BeforeUse));
+ if (I->end < Use) {
+ if (LR->isUndefIn(Undefs, I->end, BeforeUse))
+ return std::make_pair(nullptr, true);
+ extendSegmentEndTo(I, Use);
+ }
+ return std::make_pair(I->valno, false);
+ }
+
+ /// This method is used when we want to extend the segment specified
+ /// by I to end at the specified endpoint. To do this, we should
+ /// merge and eliminate all segments that this will overlap
+ /// with. The iterator is not invalidated.
+ void extendSegmentEndTo(iterator I, SlotIndex NewEnd) {
+ assert(I != segments().end() && "Not a valid segment!");
+ Segment *S = segmentAt(I);
+ VNInfo *ValNo = I->valno;
+
+ // Search for the first segment that we can't merge with.
+ iterator MergeTo = std::next(I);
+ for (; MergeTo != segments().end() && NewEnd >= MergeTo->end; ++MergeTo)
+ assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
+
+ // If NewEnd was in the middle of a segment, make sure to get its endpoint.
+ S->end = std::max(NewEnd, std::prev(MergeTo)->end);
+
+ // If the newly formed segment now touches the segment after it and if they
+ // have the same value number, merge the two segments into one segment.
+ if (MergeTo != segments().end() && MergeTo->start <= I->end &&
+ MergeTo->valno == ValNo) {
+ S->end = MergeTo->end;
+ ++MergeTo;
+ }
+
+ // Erase any dead segments.
+ segments().erase(std::next(I), MergeTo);
+ }
+
+ /// This method is used when we want to extend the segment specified
+ /// by I to start at the specified endpoint. To do this, we should
+ /// merge and eliminate all segments that this will overlap with.
+ iterator extendSegmentStartTo(iterator I, SlotIndex NewStart) {
+ assert(I != segments().end() && "Not a valid segment!");
+ Segment *S = segmentAt(I);
+ VNInfo *ValNo = I->valno;
+
+ // Search for the first segment that we can't merge with.
+ iterator MergeTo = I;
+ do {
+ if (MergeTo == segments().begin()) {
+ S->start = NewStart;
+ segments().erase(MergeTo, I);
+ return I;
+ }
+ assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
+ --MergeTo;
+ } while (NewStart <= MergeTo->start);
+
+ // If we start in the middle of another segment, just delete a range and
+ // extend that segment.
+ if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) {
+ segmentAt(MergeTo)->end = S->end;
+ } else {
+ // Otherwise, extend the segment right after.
+ ++MergeTo;
+ Segment *MergeToSeg = segmentAt(MergeTo);
+ MergeToSeg->start = NewStart;
+ MergeToSeg->end = S->end;
+ }
+
+ segments().erase(std::next(MergeTo), std::next(I));
+ return MergeTo;
+ }
+
+ iterator addSegment(Segment S) {
+ SlotIndex Start = S.start, End = S.end;
+ iterator I = impl().findInsertPos(S);
+
+ // If the inserted segment starts in the middle or right at the end of
+ // another segment, just extend that segment to contain the segment of S.
+ if (I != segments().begin()) {
+ iterator B = std::prev(I);
+ if (S.valno == B->valno) {
+ if (B->start <= Start && B->end >= Start) {
+ extendSegmentEndTo(B, End);
+ return B;
+ }
+ } else {
+ // Check to make sure that we are not overlapping two live segments with
+ // different valno's.
+ assert(B->end <= Start &&
+ "Cannot overlap two segments with differing ValID's"
+ " (did you def the same reg twice in a MachineInstr?)");
+ }
+ }
+
+ // Otherwise, if this segment ends in the middle of, or right next
+ // to, another segment, merge it into that segment.
+ if (I != segments().end()) {
+ if (S.valno == I->valno) {
+ if (I->start <= End) {
+ I = extendSegmentStartTo(I, Start);
+
+ // If S is a complete superset of a segment, we may need to grow its
+ // endpoint as well.
+ if (End > I->end)
+ extendSegmentEndTo(I, End);
+ return I;
+ }
+ } else {
+ // Check to make sure that we are not overlapping two live segments with
+ // different valno's.
+ assert(I->start >= End &&
+ "Cannot overlap two segments with differing ValID's");
+ }
+ }
+
+ // Otherwise, this is just a new segment that doesn't interact with
+ // anything.
+ // Insert it.
+ return segments().insert(I, S);
+ }
+
+private:
+ ImplT &impl() { return *static_cast<ImplT *>(this); }
+
+ CollectionT &segments() { return impl().segmentsColl(); }
+
+ Segment *segmentAt(iterator I) { return const_cast<Segment *>(&(*I)); }
+};
+
+//===----------------------------------------------------------------------===//
+// Instantiation of the methods for calculation of live ranges
+// based on a segment vector.
+//===----------------------------------------------------------------------===//
+
+class CalcLiveRangeUtilVector;
+using CalcLiveRangeUtilVectorBase =
+ CalcLiveRangeUtilBase<CalcLiveRangeUtilVector, LiveRange::iterator,
+ LiveRange::Segments>;
+
+class CalcLiveRangeUtilVector : public CalcLiveRangeUtilVectorBase {
+public:
+ CalcLiveRangeUtilVector(LiveRange *LR) : CalcLiveRangeUtilVectorBase(LR) {}
+
+private:
+ friend CalcLiveRangeUtilVectorBase;
+
+ LiveRange::Segments &segmentsColl() { return LR->segments; }
+
+ void insertAtEnd(const Segment &S) { LR->segments.push_back(S); }
+
+ iterator find(SlotIndex Pos) { return LR->find(Pos); }
+
+ iterator findInsertPos(Segment S) { return llvm::upper_bound(*LR, S.start); }
+};
+
+//===----------------------------------------------------------------------===//
+// Instantiation of the methods for calculation of live ranges
+// based on a segment set.
+//===----------------------------------------------------------------------===//
+
+class CalcLiveRangeUtilSet;
+using CalcLiveRangeUtilSetBase =
+ CalcLiveRangeUtilBase<CalcLiveRangeUtilSet, LiveRange::SegmentSet::iterator,
+ LiveRange::SegmentSet>;
+
+class CalcLiveRangeUtilSet : public CalcLiveRangeUtilSetBase {
+public:
+ CalcLiveRangeUtilSet(LiveRange *LR) : CalcLiveRangeUtilSetBase(LR) {}
+
+private:
+ friend CalcLiveRangeUtilSetBase;
+
+ LiveRange::SegmentSet &segmentsColl() { return *LR->segmentSet; }
+
+ void insertAtEnd(const Segment &S) {
+ LR->segmentSet->insert(LR->segmentSet->end(), S);
+ }
+
+ iterator find(SlotIndex Pos) {
+ iterator I =
+ LR->segmentSet->upper_bound(Segment(Pos, Pos.getNextSlot(), nullptr));
+ if (I == LR->segmentSet->begin())
+ return I;
+ iterator PrevI = std::prev(I);
+ if (Pos < (*PrevI).end)
+ return PrevI;
+ return I;
+ }
+
+ iterator findInsertPos(Segment S) {
+ iterator I = LR->segmentSet->upper_bound(S);
+ if (I != LR->segmentSet->end() && !(S.start < *I))
+ ++I;
+ return I;
+ }
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// LiveRange methods
+//===----------------------------------------------------------------------===//
+
+LiveRange::iterator LiveRange::find(SlotIndex Pos) {
+ // This algorithm is basically std::upper_bound.
+ // Unfortunately, std::upper_bound cannot be used with mixed types until we
+ // adopt C++0x. Many libraries can do it, but not all.
+ if (empty() || Pos >= endIndex())
+ return end();
+ iterator I = begin();
+ size_t Len = size();
+ do {
+ size_t Mid = Len >> 1;
+ if (Pos < I[Mid].end) {
+ Len = Mid;
+ } else {
+ I += Mid + 1;
+ Len -= Mid + 1;
+ }
+ } while (Len);
+ return I;
+}
+
+VNInfo *LiveRange::createDeadDef(SlotIndex Def, VNInfo::Allocator &VNIAlloc) {
+ // Use the segment set, if it is available.
+ if (segmentSet != nullptr)
+ return CalcLiveRangeUtilSet(this).createDeadDef(Def, &VNIAlloc, nullptr);
+ // Otherwise use the segment vector.
+ return CalcLiveRangeUtilVector(this).createDeadDef(Def, &VNIAlloc, nullptr);
+}
+
+VNInfo *LiveRange::createDeadDef(VNInfo *VNI) {
+ // Use the segment set, if it is available.
+ if (segmentSet != nullptr)
+ return CalcLiveRangeUtilSet(this).createDeadDef(VNI->def, nullptr, VNI);
+ // Otherwise use the segment vector.
+ return CalcLiveRangeUtilVector(this).createDeadDef(VNI->def, nullptr, VNI);
+}
+
+// overlaps - Return true if the intersection of the two live ranges is
+// not empty.
+//
+// An example for overlaps():
+//
+// 0: A = ...
+// 4: B = ...
+// 8: C = A + B ;; last use of A
+//
+// The live ranges should look like:
+//
+// A = [3, 11)
+// B = [7, x)
+// C = [11, y)
+//
+// A->overlaps(C) should return false since we want to be able to join
+// A and C.
+//
+bool LiveRange::overlapsFrom(const LiveRange& other,
+ const_iterator StartPos) const {
+ assert(!empty() && "empty range");
+ const_iterator i = begin();
+ const_iterator ie = end();
+ const_iterator j = StartPos;
+ const_iterator je = other.end();
+
+ assert((StartPos->start <= i->start || StartPos == other.begin()) &&
+ StartPos != other.end() && "Bogus start position hint!");
+
+ if (i->start < j->start) {
+ i = std::upper_bound(i, ie, j->start);
+ if (i != begin()) --i;
+ } else if (j->start < i->start) {
+ ++StartPos;
+ if (StartPos != other.end() && StartPos->start <= i->start) {
+ assert(StartPos < other.end() && i < end());
+ j = std::upper_bound(j, je, i->start);
+ if (j != other.begin()) --j;
+ }
+ } else {
+ return true;
+ }
+
+ if (j == je) return false;
+
+ while (i != ie) {
+ if (i->start > j->start) {
+ std::swap(i, j);
+ std::swap(ie, je);
+ }
+
+ if (i->end > j->start)
+ return true;
+ ++i;
+ }
+
+ return false;
+}
+
+bool LiveRange::overlaps(const LiveRange &Other, const CoalescerPair &CP,
+ const SlotIndexes &Indexes) const {
+ assert(!empty() && "empty range");
+ if (Other.empty())
+ return false;
+
+ // Use binary searches to find initial positions.
+ const_iterator I = find(Other.beginIndex());
+ const_iterator IE = end();
+ if (I == IE)
+ return false;
+ const_iterator J = Other.find(I->start);
+ const_iterator JE = Other.end();
+ if (J == JE)
+ return false;
+
+ while (true) {
+ // J has just been advanced to satisfy:
+ assert(J->end >= I->start);
+ // Check for an overlap.
+ if (J->start < I->end) {
+ // I and J are overlapping. Find the later start.
+ SlotIndex Def = std::max(I->start, J->start);
+ // Allow the overlap if Def is a coalescable copy.
+ if (Def.isBlock() ||
+ !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))
+ return true;
+ }
+ // Advance the iterator that ends first to check for more overlaps.
+ if (J->end > I->end) {
+ std::swap(I, J);
+ std::swap(IE, JE);
+ }
+ // Advance J until J->end >= I->start.
+ do
+ if (++J == JE)
+ return false;
+ while (J->end < I->start);
+ }
+}
+
+/// overlaps - Return true if the live range overlaps an interval specified
+/// by [Start, End).
+bool LiveRange::overlaps(SlotIndex Start, SlotIndex End) const {
+ assert(Start < End && "Invalid range");
+ const_iterator I = std::lower_bound(begin(), end(), End);
+ return I != begin() && (--I)->end > Start;
+}
+
+bool LiveRange::covers(const LiveRange &Other) const {
+ if (empty())
+ return Other.empty();
+
+ const_iterator I = begin();
+ for (const Segment &O : Other.segments) {
+ I = advanceTo(I, O.start);
+ if (I == end() || I->start > O.start)
+ return false;
+
+ // Check adjacent live segments and see if we can get behind O.end.
+ while (I->end < O.end) {
+ const_iterator Last = I;
+ // Get next segment and abort if it was not adjacent.
+ ++I;
+ if (I == end() || Last->end != I->start)
+ return false;
+ }
+ }
+ return true;
+}
+
+/// ValNo is dead, remove it. If it is the largest value number, just nuke it
+/// (and any other deleted values neighboring it), otherwise mark it as ~1U so
+/// it can be nuked later.
+void LiveRange::markValNoForDeletion(VNInfo *ValNo) {
+ if (ValNo->id == getNumValNums()-1) {
+ do {
+ valnos.pop_back();
+ } while (!valnos.empty() && valnos.back()->isUnused());
+ } else {
+ ValNo->markUnused();
+ }
+}
+
+/// RenumberValues - Renumber all values in order of appearance and delete the
+/// remaining unused values.
+void LiveRange::RenumberValues() {
+ SmallPtrSet<VNInfo*, 8> Seen;
+ valnos.clear();
+ for (const Segment &S : segments) {
+ VNInfo *VNI = S.valno;
+ if (!Seen.insert(VNI).second)
+ continue;
+ assert(!VNI->isUnused() && "Unused valno used by live segment");
+ VNI->id = (unsigned)valnos.size();
+ valnos.push_back(VNI);
+ }
+}
+
+void LiveRange::addSegmentToSet(Segment S) {
+ CalcLiveRangeUtilSet(this).addSegment(S);
+}
+
+LiveRange::iterator LiveRange::addSegment(Segment S) {
+ // Use the segment set, if it is available.
+ if (segmentSet != nullptr) {
+ addSegmentToSet(S);
+ return end();
+ }
+ // Otherwise use the segment vector.
+ return CalcLiveRangeUtilVector(this).addSegment(S);
+}
+
+void LiveRange::append(const Segment S) {
+ // Check that the segment belongs to the back of the list.
+ assert(segments.empty() || segments.back().end <= S.start);
+ segments.push_back(S);
+}
+
+std::pair<VNInfo*,bool> LiveRange::extendInBlock(ArrayRef<SlotIndex> Undefs,
+ SlotIndex StartIdx, SlotIndex Kill) {
+ // Use the segment set, if it is available.
+ if (segmentSet != nullptr)
+ return CalcLiveRangeUtilSet(this).extendInBlock(Undefs, StartIdx, Kill);
+ // Otherwise use the segment vector.
+ return CalcLiveRangeUtilVector(this).extendInBlock(Undefs, StartIdx, Kill);
+}
+
+VNInfo *LiveRange::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) {
+ // Use the segment set, if it is available.
+ if (segmentSet != nullptr)
+ return CalcLiveRangeUtilSet(this).extendInBlock(StartIdx, Kill);
+ // Otherwise use the segment vector.
+ return CalcLiveRangeUtilVector(this).extendInBlock(StartIdx, Kill);
+}
+
+/// Remove the specified segment from this range. Note that the segment must
+/// be in a single Segment in its entirety.
+void LiveRange::removeSegment(SlotIndex Start, SlotIndex End,
+ bool RemoveDeadValNo) {
+ // Find the Segment containing this span.
+ iterator I = find(Start);
+ assert(I != end() && "Segment is not in range!");
+ assert(I->containsInterval(Start, End)
+ && "Segment is not entirely in range!");
+
+ // If the span we are removing is at the start of the Segment, adjust it.
+ VNInfo *ValNo = I->valno;
+ if (I->start == Start) {
+ if (I->end == End) {
+ if (RemoveDeadValNo) {
+ // Check if val# is dead.
+ bool isDead = true;
+ for (const_iterator II = begin(), EE = end(); II != EE; ++II)
+ if (II != I && II->valno == ValNo) {
+ isDead = false;
+ break;
+ }
+ if (isDead) {
+ // Now that ValNo is dead, remove it.
+ markValNoForDeletion(ValNo);
+ }
+ }
+
+ segments.erase(I); // Removed the whole Segment.
+ } else
+ I->start = End;
+ return;
+ }
+
+ // Otherwise if the span we are removing is at the end of the Segment,
+ // adjust the other way.
+ if (I->end == End) {
+ I->end = Start;
+ return;
+ }
+
+ // Otherwise, we are splitting the Segment into two pieces.
+ SlotIndex OldEnd = I->end;
+ I->end = Start; // Trim the old segment.
+
+ // Insert the new one.
+ segments.insert(std::next(I), Segment(End, OldEnd, ValNo));
+}
+
+/// removeValNo - Remove all the segments defined by the specified value#.
+/// Also remove the value# from value# list.
+void LiveRange::removeValNo(VNInfo *ValNo) {
+ if (empty()) return;
+ segments.erase(remove_if(*this, [ValNo](const Segment &S) {
+ return S.valno == ValNo;
+ }), end());
+ // Now that ValNo is dead, remove it.
+ markValNoForDeletion(ValNo);
+}
+
+void LiveRange::join(LiveRange &Other,
+ const int *LHSValNoAssignments,
+ const int *RHSValNoAssignments,
+ SmallVectorImpl<VNInfo *> &NewVNInfo) {
+ verify();
+
+ // Determine if any of our values are mapped. This is uncommon, so we want
+ // to avoid the range scan if not.
+ bool MustMapCurValNos = false;
+ unsigned NumVals = getNumValNums();
+ unsigned NumNewVals = NewVNInfo.size();
+ for (unsigned i = 0; i != NumVals; ++i) {
+ unsigned LHSValID = LHSValNoAssignments[i];
+ if (i != LHSValID ||
+ (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {
+ MustMapCurValNos = true;
+ break;
+ }
+ }
+
+ // If we have to apply a mapping to our base range assignment, rewrite it now.
+ if (MustMapCurValNos && !empty()) {
+ // Map the first live range.
+
+ iterator OutIt = begin();
+ OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
+ for (iterator I = std::next(OutIt), E = end(); I != E; ++I) {
+ VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
+ assert(nextValNo && "Huh?");
+
+ // If this live range has the same value # as its immediate predecessor,
+ // and if they are neighbors, remove one Segment. This happens when we
+ // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
+ if (OutIt->valno == nextValNo && OutIt->end == I->start) {
+ OutIt->end = I->end;
+ } else {
+ // Didn't merge. Move OutIt to the next segment,
+ ++OutIt;
+ OutIt->valno = nextValNo;
+ if (OutIt != I) {
+ OutIt->start = I->start;
+ OutIt->end = I->end;
+ }
+ }
+ }
+ // If we merge some segments, chop off the end.
+ ++OutIt;
+ segments.erase(OutIt, end());
+ }
+
+ // Rewrite Other values before changing the VNInfo ids.
+ // This can leave Other in an invalid state because we're not coalescing
+ // touching segments that now have identical values. That's OK since Other is
+ // not supposed to be valid after calling join();
+ for (Segment &S : Other.segments)
+ S.valno = NewVNInfo[RHSValNoAssignments[S.valno->id]];
+
+ // Update val# info. Renumber them and make sure they all belong to this
+ // LiveRange now. Also remove dead val#'s.
+ unsigned NumValNos = 0;
+ for (unsigned i = 0; i < NumNewVals; ++i) {
+ VNInfo *VNI = NewVNInfo[i];
+ if (VNI) {
+ if (NumValNos >= NumVals)
+ valnos.push_back(VNI);
+ else
+ valnos[NumValNos] = VNI;
+ VNI->id = NumValNos++; // Renumber val#.
+ }
+ }
+ if (NumNewVals < NumVals)
+ valnos.resize(NumNewVals); // shrinkify
+
+ // Okay, now insert the RHS live segments into the LHS.
+ LiveRangeUpdater Updater(this);
+ for (Segment &S : Other.segments)
+ Updater.add(S);
+}
+
+/// Merge all of the segments in RHS into this live range as the specified
+/// value number. The segments in RHS are allowed to overlap with segments in
+/// the current range, but only if the overlapping segments have the
+/// specified value number.
+void LiveRange::MergeSegmentsInAsValue(const LiveRange &RHS,
+ VNInfo *LHSValNo) {
+ LiveRangeUpdater Updater(this);
+ for (const Segment &S : RHS.segments)
+ Updater.add(S.start, S.end, LHSValNo);
+}
+
+/// MergeValueInAsValue - Merge all of the live segments of a specific val#
+/// in RHS into this live range as the specified value number.
+/// The segments in RHS are allowed to overlap with segments in the
+/// current range, it will replace the value numbers of the overlaped
+/// segments with the specified value number.
+void LiveRange::MergeValueInAsValue(const LiveRange &RHS,
+ const VNInfo *RHSValNo,
+ VNInfo *LHSValNo) {
+ LiveRangeUpdater Updater(this);
+ for (const Segment &S : RHS.segments)
+ if (S.valno == RHSValNo)
+ Updater.add(S.start, S.end, LHSValNo);
+}
+
+/// MergeValueNumberInto - This method is called when two value nubmers
+/// are found to be equivalent. This eliminates V1, replacing all
+/// segments with the V1 value number with the V2 value number. This can
+/// cause merging of V1/V2 values numbers and compaction of the value space.
+VNInfo *LiveRange::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {
+ assert(V1 != V2 && "Identical value#'s are always equivalent!");
+
+ // This code actually merges the (numerically) larger value number into the
+ // smaller value number, which is likely to allow us to compactify the value
+ // space. The only thing we have to be careful of is to preserve the
+ // instruction that defines the result value.
+
+ // Make sure V2 is smaller than V1.
+ if (V1->id < V2->id) {
+ V1->copyFrom(*V2);
+ std::swap(V1, V2);
+ }
+
+ // Merge V1 segments into V2.
+ for (iterator I = begin(); I != end(); ) {
+ iterator S = I++;
+ if (S->valno != V1) continue; // Not a V1 Segment.
+
+ // Okay, we found a V1 live range. If it had a previous, touching, V2 live
+ // range, extend it.
+ if (S != begin()) {
+ iterator Prev = S-1;
+ if (Prev->valno == V2 && Prev->end == S->start) {
+ Prev->end = S->end;
+
+ // Erase this live-range.
+ segments.erase(S);
+ I = Prev+1;
+ S = Prev;
+ }
+ }
+
+ // Okay, now we have a V1 or V2 live range that is maximally merged forward.
+ // Ensure that it is a V2 live-range.
+ S->valno = V2;
+
+ // If we can merge it into later V2 segments, do so now. We ignore any
+ // following V1 segments, as they will be merged in subsequent iterations
+ // of the loop.
+ if (I != end()) {
+ if (I->start == S->end && I->valno == V2) {
+ S->end = I->end;
+ segments.erase(I);
+ I = S+1;
+ }
+ }
+ }
+
+ // Now that V1 is dead, remove it.
+ markValNoForDeletion(V1);
+
+ return V2;
+}
+
+void LiveRange::flushSegmentSet() {
+ assert(segmentSet != nullptr && "segment set must have been created");
+ assert(
+ segments.empty() &&
+ "segment set can be used only initially before switching to the array");
+ segments.append(segmentSet->begin(), segmentSet->end());
+ segmentSet = nullptr;
+ verify();
+}
+
+bool LiveRange::isLiveAtIndexes(ArrayRef<SlotIndex> Slots) const {
+ ArrayRef<SlotIndex>::iterator SlotI = Slots.begin();
+ ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
+
+ // If there are no regmask slots, we have nothing to search.
+ if (SlotI == SlotE)
+ return false;
+
+ // Start our search at the first segment that ends after the first slot.
+ const_iterator SegmentI = find(*SlotI);
+ const_iterator SegmentE = end();
+
+ // If there are no segments that end after the first slot, we're done.
+ if (SegmentI == SegmentE)
+ return false;
+
+ // Look for each slot in the live range.
+ for ( ; SlotI != SlotE; ++SlotI) {
+ // Go to the next segment that ends after the current slot.
+ // The slot may be within a hole in the range.
+ SegmentI = advanceTo(SegmentI, *SlotI);
+ if (SegmentI == SegmentE)
+ return false;
+
+ // If this segment contains the slot, we're done.
+ if (SegmentI->contains(*SlotI))
+ return true;
+ // Otherwise, look for the next slot.
+ }
+
+ // We didn't find a segment containing any of the slots.
+ return false;
+}
+
+void LiveInterval::freeSubRange(SubRange *S) {
+ S->~SubRange();
+ // Memory was allocated with BumpPtr allocator and is not freed here.
+}
+
+void LiveInterval::removeEmptySubRanges() {
+ SubRange **NextPtr = &SubRanges;
+ SubRange *I = *NextPtr;
+ while (I != nullptr) {
+ if (!I->empty()) {
+ NextPtr = &I->Next;
+ I = *NextPtr;
+ continue;
+ }
+ // Skip empty subranges until we find the first nonempty one.
+ do {
+ SubRange *Next = I->Next;
+ freeSubRange(I);
+ I = Next;
+ } while (I != nullptr && I->empty());
+ *NextPtr = I;
+ }
+}
+
+void LiveInterval::clearSubRanges() {
+ for (SubRange *I = SubRanges, *Next; I != nullptr; I = Next) {
+ Next = I->Next;
+ freeSubRange(I);
+ }
+ SubRanges = nullptr;
+}
+
+/// For each VNI in \p SR, check whether or not that value defines part
+/// of the mask describe by \p LaneMask and if not, remove that value
+/// from \p SR.
+static void stripValuesNotDefiningMask(unsigned Reg, LiveInterval::SubRange &SR,
+ LaneBitmask LaneMask,
+ const SlotIndexes &Indexes,
+ const TargetRegisterInfo &TRI) {
+ // Phys reg should not be tracked at subreg level.
+ // Same for noreg (Reg == 0).
+ if (!Register::isVirtualRegister(Reg) || !Reg)
+ return;
+ // Remove the values that don't define those lanes.
+ SmallVector<VNInfo *, 8> ToBeRemoved;
+ for (VNInfo *VNI : SR.valnos) {
+ if (VNI->isUnused())
+ continue;
+ // PHI definitions don't have MI attached, so there is nothing
+ // we can use to strip the VNI.
+ if (VNI->isPHIDef())
+ continue;
+ const MachineInstr *MI = Indexes.getInstructionFromIndex(VNI->def);
+ assert(MI && "Cannot find the definition of a value");
+ bool hasDef = false;
+ for (ConstMIBundleOperands MOI(*MI); MOI.isValid(); ++MOI) {
+ if (!MOI->isReg() || !MOI->isDef())
+ continue;
+ if (MOI->getReg() != Reg)
+ continue;
+ if ((TRI.getSubRegIndexLaneMask(MOI->getSubReg()) & LaneMask).none())
+ continue;
+ hasDef = true;
+ break;
+ }
+
+ if (!hasDef)
+ ToBeRemoved.push_back(VNI);
+ }
+ for (VNInfo *VNI : ToBeRemoved)
+ SR.removeValNo(VNI);
+
+ // If the subrange is empty at this point, the MIR is invalid. Do not assert
+ // and let the verifier catch this case.
+}
+
+void LiveInterval::refineSubRanges(
+ BumpPtrAllocator &Allocator, LaneBitmask LaneMask,
+ std::function<void(LiveInterval::SubRange &)> Apply,
+ const SlotIndexes &Indexes, const TargetRegisterInfo &TRI) {
+ LaneBitmask ToApply = LaneMask;
+ for (SubRange &SR : subranges()) {
+ LaneBitmask SRMask = SR.LaneMask;
+ LaneBitmask Matching = SRMask & LaneMask;
+ if (Matching.none())
+ continue;
+
+ SubRange *MatchingRange;
+ if (SRMask == Matching) {
+ // The subrange fits (it does not cover bits outside \p LaneMask).
+ MatchingRange = &SR;
+ } else {
+ // We have to split the subrange into a matching and non-matching part.
+ // Reduce lanemask of existing lane to non-matching part.
+ SR.LaneMask = SRMask & ~Matching;
+ // Create a new subrange for the matching part
+ MatchingRange = createSubRangeFrom(Allocator, Matching, SR);
+ // Now that the subrange is split in half, make sure we
+ // only keep in the subranges the VNIs that touch the related half.
+ stripValuesNotDefiningMask(reg, *MatchingRange, Matching, Indexes, TRI);
+ stripValuesNotDefiningMask(reg, SR, SR.LaneMask, Indexes, TRI);
+ }
+ Apply(*MatchingRange);
+ ToApply &= ~Matching;
+ }
+ // Create a new subrange if there are uncovered bits left.
+ if (ToApply.any()) {
+ SubRange *NewRange = createSubRange(Allocator, ToApply);
+ Apply(*NewRange);
+ }
+}
+
+unsigned LiveInterval::getSize() const {
+ unsigned Sum = 0;
+ for (const Segment &S : segments)
+ Sum += S.start.distance(S.end);
+ return Sum;
+}
+
+void LiveInterval::computeSubRangeUndefs(SmallVectorImpl<SlotIndex> &Undefs,
+ LaneBitmask LaneMask,
+ const MachineRegisterInfo &MRI,
+ const SlotIndexes &Indexes) const {
+ assert(Register::isVirtualRegister(reg));
+ LaneBitmask VRegMask = MRI.getMaxLaneMaskForVReg(reg);
+ assert((VRegMask & LaneMask).any());
+ const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
+ for (const MachineOperand &MO : MRI.def_operands(reg)) {
+ if (!MO.isUndef())
+ continue;
+ unsigned SubReg = MO.getSubReg();
+ assert(SubReg != 0 && "Undef should only be set on subreg defs");
+ LaneBitmask DefMask = TRI.getSubRegIndexLaneMask(SubReg);
+ LaneBitmask UndefMask = VRegMask & ~DefMask;
+ if ((UndefMask & LaneMask).any()) {
+ const MachineInstr &MI = *MO.getParent();
+ bool EarlyClobber = MO.isEarlyClobber();
+ SlotIndex Pos = Indexes.getInstructionIndex(MI).getRegSlot(EarlyClobber);
+ Undefs.push_back(Pos);
+ }
+ }
+}
+
+raw_ostream& llvm::operator<<(raw_ostream& OS, const LiveRange::Segment &S) {
+ return OS << '[' << S.start << ',' << S.end << ':' << S.valno->id << ')';
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+LLVM_DUMP_METHOD void LiveRange::Segment::dump() const {
+ dbgs() << *this << '\n';
+}
+#endif
+
+void LiveRange::print(raw_ostream &OS) const {
+ if (empty())
+ OS << "EMPTY";
+ else {
+ for (const Segment &S : segments) {
+ OS << S;
+ assert(S.valno == getValNumInfo(S.valno->id) && "Bad VNInfo");
+ }
+ }
+
+ // Print value number info.
+ if (getNumValNums()) {
+ OS << " ";
+ unsigned vnum = 0;
+ for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;
+ ++i, ++vnum) {
+ const VNInfo *vni = *i;
+ if (vnum) OS << ' ';
+ OS << vnum << '@';
+ if (vni->isUnused()) {
+ OS << 'x';
+ } else {
+ OS << vni->def;
+ if (vni->isPHIDef())
+ OS << "-phi";
+ }
+ }
+ }
+}
+
+void LiveInterval::SubRange::print(raw_ostream &OS) const {
+ OS << " L" << PrintLaneMask(LaneMask) << ' '
+ << static_cast<const LiveRange&>(*this);
+}
+
+void LiveInterval::print(raw_ostream &OS) const {
+ OS << printReg(reg) << ' ';
+ super::print(OS);
+ // Print subranges
+ for (const SubRange &SR : subranges())
+ OS << SR;
+ OS << " weight:" << weight;
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+LLVM_DUMP_METHOD void LiveRange::dump() const {
+ dbgs() << *this << '\n';
+}
+
+LLVM_DUMP_METHOD void LiveInterval::SubRange::dump() const {
+ dbgs() << *this << '\n';
+}
+
+LLVM_DUMP_METHOD void LiveInterval::dump() const {
+ dbgs() << *this << '\n';
+}
+#endif
+
+#ifndef NDEBUG
+void LiveRange::verify() const {
+ for (const_iterator I = begin(), E = end(); I != E; ++I) {
+ assert(I->start.isValid());
+ assert(I->end.isValid());
+ assert(I->start < I->end);
+ assert(I->valno != nullptr);
+ assert(I->valno->id < valnos.size());
+ assert(I->valno == valnos[I->valno->id]);
+ if (std::next(I) != E) {
+ assert(I->end <= std::next(I)->start);
+ if (I->end == std::next(I)->start)
+ assert(I->valno != std::next(I)->valno);
+ }
+ }
+}
+
+void LiveInterval::verify(const MachineRegisterInfo *MRI) const {
+ super::verify();
+
+ // Make sure SubRanges are fine and LaneMasks are disjunct.
+ LaneBitmask Mask;
+ LaneBitmask MaxMask = MRI != nullptr ? MRI->getMaxLaneMaskForVReg(reg)
+ : LaneBitmask::getAll();
+ for (const SubRange &SR : subranges()) {
+ // Subrange lanemask should be disjunct to any previous subrange masks.
+ assert((Mask & SR.LaneMask).none());
+ Mask |= SR.LaneMask;
+
+ // subrange mask should not contained in maximum lane mask for the vreg.
+ assert((Mask & ~MaxMask).none());
+ // empty subranges must be removed.
+ assert(!SR.empty());
+
+ SR.verify();
+ // Main liverange should cover subrange.
+ assert(covers(SR));
+ }
+}
+#endif
+
+//===----------------------------------------------------------------------===//
+// LiveRangeUpdater class
+//===----------------------------------------------------------------------===//
+//
+// The LiveRangeUpdater class always maintains these invariants:
+//
+// - When LastStart is invalid, Spills is empty and the iterators are invalid.
+// This is the initial state, and the state created by flush().
+// In this state, isDirty() returns false.
+//
+// Otherwise, segments are kept in three separate areas:
+//
+// 1. [begin; WriteI) at the front of LR.
+// 2. [ReadI; end) at the back of LR.
+// 3. Spills.
+//
+// - LR.begin() <= WriteI <= ReadI <= LR.end().
+// - Segments in all three areas are fully ordered and coalesced.
+// - Segments in area 1 precede and can't coalesce with segments in area 2.
+// - Segments in Spills precede and can't coalesce with segments in area 2.
+// - No coalescing is possible between segments in Spills and segments in area
+// 1, and there are no overlapping segments.
+//
+// The segments in Spills are not ordered with respect to the segments in area
+// 1. They need to be merged.
+//
+// When they exist, Spills.back().start <= LastStart,
+// and WriteI[-1].start <= LastStart.
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void LiveRangeUpdater::print(raw_ostream &OS) const {
+ if (!isDirty()) {
+ if (LR)
+ OS << "Clean updater: " << *LR << '\n';
+ else
+ OS << "Null updater.\n";
+ return;
+ }
+ assert(LR && "Can't have null LR in dirty updater.");
+ OS << " updater with gap = " << (ReadI - WriteI)
+ << ", last start = " << LastStart
+ << ":\n Area 1:";
+ for (const auto &S : make_range(LR->begin(), WriteI))
+ OS << ' ' << S;
+ OS << "\n Spills:";
+ for (unsigned I = 0, E = Spills.size(); I != E; ++I)
+ OS << ' ' << Spills[I];
+ OS << "\n Area 2:";
+ for (const auto &S : make_range(ReadI, LR->end()))
+ OS << ' ' << S;
+ OS << '\n';
+}
+
+LLVM_DUMP_METHOD void LiveRangeUpdater::dump() const {
+ print(errs());
+}
+#endif
+
+// Determine if A and B should be coalesced.
+static inline bool coalescable(const LiveRange::Segment &A,
+ const LiveRange::Segment &B) {
+ assert(A.start <= B.start && "Unordered live segments.");
+ if (A.end == B.start)
+ return A.valno == B.valno;
+ if (A.end < B.start)
+ return false;
+ assert(A.valno == B.valno && "Cannot overlap different values");
+ return true;
+}
+
+void LiveRangeUpdater::add(LiveRange::Segment Seg) {
+ assert(LR && "Cannot add to a null destination");
+
+ // Fall back to the regular add method if the live range
+ // is using the segment set instead of the segment vector.
+ if (LR->segmentSet != nullptr) {
+ LR->addSegmentToSet(Seg);
+ return;
+ }
+
+ // Flush the state if Start moves backwards.
+ if (!LastStart.isValid() || LastStart > Seg.start) {
+ if (isDirty())
+ flush();
+ // This brings us to an uninitialized state. Reinitialize.
+ assert(Spills.empty() && "Leftover spilled segments");
+ WriteI = ReadI = LR->begin();
+ }
+
+ // Remember start for next time.
+ LastStart = Seg.start;
+
+ // Advance ReadI until it ends after Seg.start.
+ LiveRange::iterator E = LR->end();
+ if (ReadI != E && ReadI->end <= Seg.start) {
+ // First try to close the gap between WriteI and ReadI with spills.
+ if (ReadI != WriteI)
+ mergeSpills();
+ // Then advance ReadI.
+ if (ReadI == WriteI)
+ ReadI = WriteI = LR->find(Seg.start);
+ else
+ while (ReadI != E && ReadI->end <= Seg.start)
+ *WriteI++ = *ReadI++;
+ }
+
+ assert(ReadI == E || ReadI->end > Seg.start);
+
+ // Check if the ReadI segment begins early.
+ if (ReadI != E && ReadI->start <= Seg.start) {
+ assert(ReadI->valno == Seg.valno && "Cannot overlap different values");
+ // Bail if Seg is completely contained in ReadI.
+ if (ReadI->end >= Seg.end)
+ return;
+ // Coalesce into Seg.
+ Seg.start = ReadI->start;
+ ++ReadI;
+ }
+
+ // Coalesce as much as possible from ReadI into Seg.
+ while (ReadI != E && coalescable(Seg, *ReadI)) {
+ Seg.end = std::max(Seg.end, ReadI->end);
+ ++ReadI;
+ }
+
+ // Try coalescing Spills.back() into Seg.
+ if (!Spills.empty() && coalescable(Spills.back(), Seg)) {
+ Seg.start = Spills.back().start;
+ Seg.end = std::max(Spills.back().end, Seg.end);
+ Spills.pop_back();
+ }
+
+ // Try coalescing Seg into WriteI[-1].
+ if (WriteI != LR->begin() && coalescable(WriteI[-1], Seg)) {
+ WriteI[-1].end = std::max(WriteI[-1].end, Seg.end);
+ return;
+ }
+
+ // Seg doesn't coalesce with anything, and needs to be inserted somewhere.
+ if (WriteI != ReadI) {
+ *WriteI++ = Seg;
+ return;
+ }
+
+ // Finally, append to LR or Spills.
+ if (WriteI == E) {
+ LR->segments.push_back(Seg);
+ WriteI = ReadI = LR->end();
+ } else
+ Spills.push_back(Seg);
+}
+
+// Merge as many spilled segments as possible into the gap between WriteI
+// and ReadI. Advance WriteI to reflect the inserted instructions.
+void LiveRangeUpdater::mergeSpills() {
+ // Perform a backwards merge of Spills and [SpillI;WriteI).
+ size_t GapSize = ReadI - WriteI;
+ size_t NumMoved = std::min(Spills.size(), GapSize);
+ LiveRange::iterator Src = WriteI;
+ LiveRange::iterator Dst = Src + NumMoved;
+ LiveRange::iterator SpillSrc = Spills.end();
+ LiveRange::iterator B = LR->begin();
+
+ // This is the new WriteI position after merging spills.
+ WriteI = Dst;
+
+ // Now merge Src and Spills backwards.
+ while (Src != Dst) {
+ if (Src != B && Src[-1].start > SpillSrc[-1].start)
+ *--Dst = *--Src;
+ else
+ *--Dst = *--SpillSrc;
+ }
+ assert(NumMoved == size_t(Spills.end() - SpillSrc));
+ Spills.erase(SpillSrc, Spills.end());
+}
+
+void LiveRangeUpdater::flush() {
+ if (!isDirty())
+ return;
+ // Clear the dirty state.
+ LastStart = SlotIndex();
+
+ assert(LR && "Cannot add to a null destination");
+
+ // Nothing to merge?
+ if (Spills.empty()) {
+ LR->segments.erase(WriteI, ReadI);
+ LR->verify();
+ return;
+ }
+
+ // Resize the WriteI - ReadI gap to match Spills.
+ size_t GapSize = ReadI - WriteI;
+ if (GapSize < Spills.size()) {
+ // The gap is too small. Make some room.
+ size_t WritePos = WriteI - LR->begin();
+ LR->segments.insert(ReadI, Spills.size() - GapSize, LiveRange::Segment());
+ // This also invalidated ReadI, but it is recomputed below.
+ WriteI = LR->begin() + WritePos;
+ } else {
+ // Shrink the gap if necessary.
+ LR->segments.erase(WriteI + Spills.size(), ReadI);
+ }
+ ReadI = WriteI + Spills.size();
+ mergeSpills();
+ LR->verify();
+}
+
+unsigned ConnectedVNInfoEqClasses::Classify(const LiveRange &LR) {
+ // Create initial equivalence classes.
+ EqClass.clear();
+ EqClass.grow(LR.getNumValNums());
+
+ const VNInfo *used = nullptr, *unused = nullptr;
+
+ // Determine connections.
+ for (const VNInfo *VNI : LR.valnos) {
+ // Group all unused values into one class.
+ if (VNI->isUnused()) {
+ if (unused)
+ EqClass.join(unused->id, VNI->id);
+ unused = VNI;
+ continue;
+ }
+ used = VNI;
+ if (VNI->isPHIDef()) {
+ const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
+ assert(MBB && "Phi-def has no defining MBB");
+ // Connect to values live out of predecessors.
+ for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI)
+ if (const VNInfo *PVNI = LR.getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
+ EqClass.join(VNI->id, PVNI->id);
+ } else {
+ // Normal value defined by an instruction. Check for two-addr redef.
+ // FIXME: This could be coincidental. Should we really check for a tied
+ // operand constraint?
+ // Note that VNI->def may be a use slot for an early clobber def.
+ if (const VNInfo *UVNI = LR.getVNInfoBefore(VNI->def))
+ EqClass.join(VNI->id, UVNI->id);
+ }
+ }
+
+ // Lump all the unused values in with the last used value.
+ if (used && unused)
+ EqClass.join(used->id, unused->id);
+
+ EqClass.compress();
+ return EqClass.getNumClasses();
+}
+
+void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[],
+ MachineRegisterInfo &MRI) {
+ // Rewrite instructions.
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(LI.reg),
+ RE = MRI.reg_end(); RI != RE;) {
+ MachineOperand &MO = *RI;
+ MachineInstr *MI = RI->getParent();
+ ++RI;
+ const VNInfo *VNI;
+ if (MI->isDebugValue()) {
+ // DBG_VALUE instructions don't have slot indexes, so get the index of
+ // the instruction before them. The value is defined there too.
+ SlotIndex Idx = LIS.getSlotIndexes()->getIndexBefore(*MI);
+ VNI = LI.Query(Idx).valueOut();
+ } else {
+ SlotIndex Idx = LIS.getInstructionIndex(*MI);
+ LiveQueryResult LRQ = LI.Query(Idx);
+ VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
+ }
+ // In the case of an <undef> use that isn't tied to any def, VNI will be
+ // NULL. If the use is tied to a def, VNI will be the defined value.
+ if (!VNI)
+ continue;
+ if (unsigned EqClass = getEqClass(VNI))
+ MO.setReg(LIV[EqClass-1]->reg);
+ }
+
+ // Distribute subregister liveranges.
+ if (LI.hasSubRanges()) {
+ unsigned NumComponents = EqClass.getNumClasses();
+ SmallVector<unsigned, 8> VNIMapping;
+ SmallVector<LiveInterval::SubRange*, 8> SubRanges;
+ BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator();
+ for (LiveInterval::SubRange &SR : LI.subranges()) {
+ // Create new subranges in the split intervals and construct a mapping
+ // for the VNInfos in the subrange.
+ unsigned NumValNos = SR.valnos.size();
+ VNIMapping.clear();
+ VNIMapping.reserve(NumValNos);
+ SubRanges.clear();
+ SubRanges.resize(NumComponents-1, nullptr);
+ for (unsigned I = 0; I < NumValNos; ++I) {
+ const VNInfo &VNI = *SR.valnos[I];
+ unsigned ComponentNum;
+ if (VNI.isUnused()) {
+ ComponentNum = 0;
+ } else {
+ const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
+ assert(MainRangeVNI != nullptr
+ && "SubRange def must have corresponding main range def");
+ ComponentNum = getEqClass(MainRangeVNI);
+ if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
+ SubRanges[ComponentNum-1]
+ = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
+ }
+ }
+ VNIMapping.push_back(ComponentNum);
+ }
+ DistributeRange(SR, SubRanges.data(), VNIMapping);
+ }
+ LI.removeEmptySubRanges();
+ }
+
+ // Distribute main liverange.
+ DistributeRange(LI, LIV, EqClass);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-12 01:27:22 +0000